Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S937576AbXHHVZ3 (ORCPT ); Wed, 8 Aug 2007 17:25:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933849AbXHHVZU (ORCPT ); Wed, 8 Aug 2007 17:25:20 -0400 Received: from smtp2.linux-foundation.org ([207.189.120.14]:58577 "EHLO smtp2.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932093AbXHHVZS (ORCPT ); Wed, 8 Aug 2007 17:25:18 -0400 Date: Wed, 8 Aug 2007 14:21:46 -0700 From: Andrew Morton To: "Martin J. Bligh" Cc: Christoph Hellwig , J??rn Engel , Ingo Molnar , Jeff Garzik , Linus Torvalds , Peter Zijlstra , linux-mm@kvack.org, Linux Kernel Mailing List , miklos@szeredi.hu, neilb@suse.de, dgc@sgi.com, tomoki.sekiyama.qu@hitachi.com, nikita@clusterfs.com, trond.myklebust@fys.uio.no, yingchao.zhou@gmail.com, richard@rsk.demon.co.uk, david@lang.hm Subject: Re: [PATCH 00/23] per device dirty throttling -v8 Message-Id: <20070808142146.c85ab8d7.akpm@linux-foundation.org> In-Reply-To: <46BA3137.3020701@mbligh.org> References: <20070804070737.GA940@elte.hu> <20070804103347.GA1956@elte.hu> <20070804163733.GA31001@elte.hu> <46B4C0A8.1000902@garzik.org> <20070804191205.GA24723@lazybastard.org> <20070804192130.GA25346@elte.hu> <20070804192615.GA25600@lazybastard.org> <20070804194259.GA25753@lazybastard.org> <20070805203602.GB25107@infradead.org> <46BA3137.3020701@mbligh.org> X-Mailer: Sylpheed version 2.2.7 (GTK+ 2.8.6; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 862 Lines: 22 On Wed, 08 Aug 2007 14:10:15 -0700 "Martin J. Bligh" wrote: > Why isn't this easily fixable by just adding an additional dirty > flag that says atime has changed? Then we only cause a write > when we remove the inode from the inode cache, if only atime > is updated. I think that could be made to work, and it would fix the performance issue. It is a behaviour change. At present ext3 (for example) commits everything every five seconds. After a change like this, a crash+recovery could cause a file's atime to go backwards by an arbitrarily large time interval - it could easily be months. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/